Tablet computer systems, electronic book (e-book) readers, smart phones, and other types of portable devices are increasingly popular. These types of devices have features in common, such as high resolution touchscreens that provide an easy-to-use and intuitive user interface and that allow users to interact directly with what is being displayed.
In an e-reader, for example, a page of an e-book is rendered and displayed. The electronic version of the page that is displayed looks very much like the conventional non-electronic version of the page.
One advantage that an e-book has over a conventional non-electronic book is that characteristics of the electronic page can be changed to satisfy a user's preferences. For example, if the user prefers larger-sized text, the user can change the size of the font being used.
However, changing a characteristic such as font size, while not difficult, nevertheless requires the user to perform a series of operations that may not be intuitive. First, the user opens a menu, usually by tapping the e-book's touchscreen. Next, the user selects (e.g., touches) an icon within that menu, to open a window that will allow the user to change font size. Within that window, the user opens another menu (e.g., for advanced settings) that opens up a sample window that includes text. An option for controlling font size (e.g., a slider bar) is also displayed; the user moves a slider along the bar to adjust font size, and the size of the text in the sample window changes as the user moves the slider. After deciding on a new font size, the user then needs to actively close the windows, menus, etc., that were opened in order to return and view the electronic page without obstruction. All told, multiple steps are needed in order to change font size.
As an alternative, some e-books offer a simpler approach. An option for controlling font size (e.g., a slider bar) is displayed when the user taps the touchscreen; the user moves a slider along the bar to select a new font size. After a perceivable delay, the electronic page being displayed is re-rendered using the new font size. The reason for the delay is that, in order to re-render the electronic page being displayed, other pages of the electronic book—perhaps an entire chapter—have to be re-rendered in the background for proper pagination. If the user is not satisfied with the new font size, the process is repeated, causing another delay.